There were no great innovations in technology in sight. The tank was the most promising offensive tool, but it remained a primitive weapon with great potential but no proven value. Generals like Douglas Haig and Robert Nivelle had to rely on a mixture of infantry and artillery. Even by the standards of the first two years of the war, the failures of 1916 and 1917 and their consequences were unprecedented. A striking fact is the lack of development in the minds of senior commanders. In May 1917, after two years of futile and bloody efforts, Haig wrote to his army commanders, "We are now justified in believing that one great victory, equal to those already gained, may turn the scales finally." As his biographer Gerard De Groot has pointed out, "The memo was a virtual carbon copy of those issued before and during the Somme offensive." It should be noted that the Germans too had an offensive mentality, and their leaders were willing to suffer huge casualties to use it in the search for a decisive victory. The assault on France through Belgium in 1914 was an example of Napoleonic principles at work: Germany hoped to annihilate the French army and to drive France from the war in less than two months. In the closing months of 1914, Falkenhayn conducted his assault on the British at Ypres with the same reckless loss of life the French were to suffer the following year. During four days of the carnage in northwestern Belgium, the Bavarian regiment in which young Adolf Hitler served lost 3,000 men killed or wounded from its total strength of 3,600.6 in the east, Hindenburg and Ludendorff repeatedly badgered Falkenhayn for the troops that would make a decisive assault on the Russians possible. The brilliant advance that began with the breakthroiJgh at Gorlice-Tamow in May 1915 seemed evidence that German arms could drive Russia from the war. But Germany's inferiority in numbers kept its forces mainly on the defensive in the west between November 1914 and March 1918—with the important exception of the battle of attrifion Falkenhayn conducted against the French at Verdun. The Germans nonetheless excelled at the ferocious counterattack. At Loos, in October 1915, on the Somme in 1916, at Passchendaele and Cambrai in 1917, Allied advances routinely faced immediate and devastating return blows from the enemy. The spirited German counterattack at Loos, which recaptured the key Hohenzollem Redoubt, prompted even British General Sir Henry Wilson to comment, "Stout fellows those Boshes."